A novel extremely halophilic archaeon (archaebacterium) was isolated from rock salt obtained from an Austrian salt mine. The deposition of the salt is thought to have occurred during the Permian period (225 x 106 to 280 x 10(exp 6) years ago). This organism grew over a pH range of 6.8 to 9.5. Electron microscopy revealed cocci in tetrads or larger clusters. The partial 16S rRNA sequences, polar lipid composition, and menaquinone content suggested that this organism was related to members of the genus Halococcus, while the whole-cell protein patterns, the presence of several unknown lipids, and the presence of pink pigmentation indicated that it was different from previously described coccoid halophiles. We propose that this isolate should be recognized as a new species and should be named Halococcus salifodinae. The type strain is Bl(sub p) (= ATCC 51437 = DSM 8989). A chemotaxonomically similar microorganism was isolated from a British salt mine.